For example, an electric cable used for a pacemaker causing heartbeats by providing periodic electric stimulation to a heart or an electric cable used for a small-sized robot assisting movement of limbs of the human body is required to be flexible in accordance with an operation of a wiring site, and to have resistance to repeated bending or bending with an extremely small curvature, so that an electric cable which is wound to have a coil shape has been used in order to satisfy such durability.
As such an existing coiled electric cable, Patent Document 1 discloses a coiled electric cable formed in a coil shape by arranging a plurality of conductor base lines in parallel. The conductor base lines are composed of: a clad structure whose outer periphery of a center material made of silver or copper is integrated with an outer material made of stainless steel or a cobalt-based alloy; and an insulation coating layer made of a fluorine resin or the like which covers the outer periphery of the clad structure. The coiled electric cable is stretchable because the plurality of the conductor base lines are arranged in parallel to form a coil shape, has low electric resistance because the center material is formed of silver or copper, and have high tensile strength because the outer material is formed of stainless steel or a cobalt-based alloy. Consequently, the durability of the coiled electric cable can be increased.